The present invention relates to an arrangement for mounting a refractory plate, i.e. a stationary bottom or lower plate or a sliding plate, to a frame for use in a sliding gate or sliding closure unit of the type for controlling the discharge of molten metal from a metallurgical vessel.
This type of assembly of metallic frame and refractory plate has the same general function in various types of sliding closure units, i.e. of the linear, rotary or pivotal movement type, and whether of the two-plate or three-plate type. In such arrangements, typically the refractory plate is mounted in the metallic frame by use of a refractory mortar. This arrangement however has the disadvantage that it involves a difficult mounting and adjustment procedure. A further disadvantage is that breaking out or removal of a worn refractory plate from the metallic frame is equally awkward.
One known arrangement to overcome such disadvantages is as disclosed, for example, in DE-OS No. 26 20 423, wherein a refractory plate without a metal jacket is mounted in a frame by clamping without mortar by the use of adjustable frame sections constructed as clamping jaws or movable frame portions. A substantial disadvantage of this type of arrangement however is that the fastening forces do not act on the periphery of the plate in an even manner, but rather at concentrated portions of the peripheral area of the plate. As a result, the plate is subjected to tensions, particularly in cooperation with the thermal stresses to which the plate is subjected during operation. These tensions cause deformation of the plate and particularly lead to the formation of cracks therein. The extent of such cracks is accelerated by the uneven peripheral support of the plate. As a result, the plate has a relatively short service life and must be frequently replaced.
Similar disadvantages result from the arrangement disclosed in DE-GM No. 80 13 402, wherein a refractory plate is clamped between two parts of a mounting frame which are connected together by bolts in a detachable manner, and the thus assembled integral unit then is inserted into a frame of the sliding closure unit and is fastened therein by dowels.
To overcome the problem of cracking of the refractory plate due to the above known arrangements, it further is known to provide the refractory plate with a peripheral sheet metal jacket which is integrally and firmly attached to the plate. The resultant assembly then is mounted in a frame of the sliding closure unit. An example of this arrangement is disclosed in Austrian Patent No. 371,394. However, this arrangement has the disadvantages of being expensive to manufacture and being extremely uneconomical since not only the worn plate, but also its sheet metal jacket must be discarded when the refractory plate requires replacement.